We establish P=W and PI=WI conjectures for character varieties with structural group GLn and SLn which admit a symplectic resolution, i.e. for genus 1 and arbitrary rank, and genus 2 and rank 2. We formulate the P=W conjecture for resolution, and prove it for symplectic resolutions. We exploit the topology of birational and quasi-étale modifications of Dolbeault moduli spaces of Higgs bundles. To this end, we prove auxiliary results of independent interest, like the construction of a relative compactification of the Hodge moduli space for reductive algebraic groups, or the intersection theory of some singular Lagrangian cycles. In particular, we study in detail a Dolbeault moduli space which is specialization of the singular irreducible holomorphic symplectic variety of type O'Grady 6.
PreliminariesIn this section we introduces preliminary notions and results which will be useful throughout the paper. For further details we refer to [3,29,30,18].
Perverse sheavesAn algebraic variety X is an irreducible separated scheme of finite type over C. Denote by D b c (X) the bounded derived category of Q-constructible complexes on X. Let D : D b c (X) → D b c (X) be the Verdier duality functor. The full subcategoriesX) of the t-structure is the abelian category of perverse sheaves. The truncation functors are denoted p τ ≤k : D b c (X) → p D b ≤k (X), p τ ≥k : D b c (X) → p D b ≥k (X), and the perverse cohomology functors are p H k := p τ ≤k p τ ≥k : D b c (X) → Perv(X).